This invention relates generally to a method an apparatus for detecting a burner flame, and, more particularly, to methods and apparatus for igniting a flame of a gas burner.
Some gas-fired cooktops include ignition devices that generate a spark to ignite a burner when applicable fuel valves are opened to deliver fuel to the burner. One type of ignition device also continuously monitors the burner utilizing the rectifying effect of the burner flame and therefore detects the presence of a flame on the burner after ignition. If the flame extinguishes when the fuel valve is opened, the ignition device generates a spark to reignite the burner flame. See for example, U.S. Pat. Nos. 5,619,303 and 4,519,771. The circuitry of the ignition device is sometimes packaged in a module that is electrically connected between a cooktop power supply and the cooktop burner system. Power supply phase conductors and neutral conductors are input to the module, and the module output is fed to an electrode and an igniter for ignition or reignition of the burner flame as necessary.
Known ignition modules for gas-fired burners, however, are susceptible to malfunctions in use. For example, the phase and neutral conductors of an alternating current power supply can sometimes be reversed and cause the modules to continuously spark. In addition, the modules are often sensitive to voltage on the neutral conductor which desensitizes the flame detection circuit and can lead to continuously generated sparks despite the presence of a flame on a burner. Still further, proper operation of the ignition modules is dependent upon proper connection of ground conductors and neutral conductors in electrical junction boxes that feed the ignition module in use. If the electrical junction box is not properly wired, the ignition module will continuously spark. Unnecessary sparking of the ignition module reduces energy efficiency and also shortens a useable life of the ignition module.